1. Technical Field
The present invention relates to a resonator element and a resonator device, an electronic apparatus, and a moving object using the resonator element, and a method of manufacturing the resonator element.
2. Related Art
Electronic devices including thin vibrators and oscillators are widely used in small information apparatuses such as HDDs (hard disc drives), mobile computers, or IC cards, mobile communication apparatuses such as cell phones, car phones, or paging systems, etc. For example, in a piezoelectric vibrator as an electronic device disclosed in Patent Document 1 (JP-A-2008-22413), a tuning-fork crystal vibrating reed as a resonator element is mounted (connected) with vibrating arms floated within a package including a base part having a thin box shape and a lid member of a thin plate. In the piezoelectric vibrator having the configuration, when an impact is externally applied, the vibrating arms of the tuning-fork crystal vibrating reed may bend due to the impact, the ends of the vibrating arms may come into contact with the inner bottom surface of the package, and the vibrating arms may be broken.
To suppress the breakage of the vibrating arms, for example, in a piezoelectric vibrator disclosed in Patent Document 2 (JP-A-2009-253622), impact resistance is improved by providing cutout portions on the ends of the vibrating arms of the tuning-fork crystal vibrating reed. In the piezoelectric vibrator disclosed in Patent Document 2, even when the vibrating arms of the tuning-fork crystal vibrating reed bend due to an external impact or the like and the ends of the vibrating arms come into contact with the inner bottom surface of the package, the impact by the cutout portions (C-chamfers, R-chamfers, stepped portions) is dispersed, and prevention of breakage of the tuning-fork crystal vibrating reed may be expected.
However, polishing or grinding by machining is necessary for the C-chamfers and the R-chamfers provided on the ends of the vibrating arms of the piezoelectric vibrator disclosed in Patent Document 2. In the case of mass production, there is the first problem that large variations among individuals are caused in slope angles and shapes and stable predetermined chamfering with small variations is extremely difficult.
Further, in the pair of the vibrating arms, there is the second problem that a large difference is caused between the chamfered shapes of the arms.
Furthermore, in the case where weights are provided at the end sides of the vibrating arms, there is the third problem that breakage of the vibrating reed due to contact with the substrate on which the vibrating reed is mounted should be reduced while the weight effect is maintained.
In addition, it is necessary to newly add a step for the stepped portions or double-stepped portions provided on the ends of the vibrating arms of the piezoelectric vibrator, and there is the fourth problem of cost increase.